Purpose: More than 50 inherited retinal diseases are known, with rod photoreceptor functional loss serving as an early indicator in nearly half of them. The “optoretinogram” is a relatively new assay that detects optical changes in cells in response to stimuli. This tool has excellent potential for providing insights into the earliest functional changes of rod photoreceptors, with the potential to assist in the early detection, monitoring, and treatment of retinal diseases. Methods: In this work